# include <iostream>
using namespace std
void
DeleteChars(char * first, char * second)
{if (first == NULL | | second == NULL)
return
// hashTable标记字符是否在字符串second中出现...
bool
hashTable[256];
memset(hashTable, 0, sizeof(hashTable));
size_t
len1 = strlen(first);
size_t
len2 = strlen(second);
// 扫描字符串second，在hashTable中标记出现的字符
for (int i=0;i < len2;i++)
    if (!hashTable[second[i]])
        hashTable[second[i]] = true;

char * fast = first;
char * slow = first;

// 删除first中出现在second中的字符
while (*fast != '\0')
    {
    if (!hashTable[* fast])
    {
        *slow = *fast;
    ++slow;
    }
    ++fast;
    }

    *slow = '\0';
    }
    int
    main()
    {
    char
    first[] = "They are students";
    char
    second[] = "aeiou";
    DeleteChars(first, second);
    cout << first << endl;
    system("pause");
    return 0;
    }